204431509 has 2 divisors, whose sum is σ = 204431510. Its totient is φ = 204431508.

The previous prime is 204431483. The next prime is 204431569. The reversal of 204431509 is 905134402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 167184900 + 37246609 = 12930^2 + 6103^2 .

It is a cyclic number.

It is not a de Polignac number, because 204431509 - 2⁹ = 204430997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (204431569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 102215754 + 102215755.

It is an arithmetic number, because the mean of its divisors is an integer number (102215755).

Almost surely, 2^204431509 is an apocalyptic number.

It is an amenable number.

204431509 is a deficient number, since it is larger than the sum of its proper divisors (1).

204431509 is an equidigital number, since it uses as much as digits as its factorization.

204431509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 204431509 is about 14297.9547138743. The cubic root of 204431509 is about 589.0913034658.

It can be divided in two parts, 20443 and 1509, that added together give a cube (21952 = 28³).

The spelling of 204431509 in words is "two hundred four million, four hundred thirty-one thousand, five hundred nine".